CFC Phase Out
On a worldwide basis, the great majority of patients who receive inhalation therapy rely on the MDI (Metered Dose Inhaler) for delivery of their medication. MDIs account for 70% of all inhalation therapy in the countries with the largest population of patients with respiratory disease. For approximately forty years prior to 1999, MDIs used chlorofluorocarbons (CFCs) as propellants.
In response to the Montreal Protocol on Substances which Deplete the Ozone Layer, pharmaceutical firms and others have evaluated potential alternative propellants for their safety and performance in MDIs. In the course of this review, HFA 134a and HFA 227ea emerged as the only propellants suitable to replace CFCs for pharmaceutical use.
The replacement of CFCs in MDIs has been one of the most significant challenges to face the pharmaceutical industry in recent years. The industry transition to HFAs is essentially complete for the developed world (non-Article 5 Parties under the Montreal Protocol) and well under way in developing countries (Article 5 Parties under the Montreal Protocol). The transition has already cost an estimated £1 billion. Mexichem Fluor continues to work alongside pharmaceutical companies, in the developing world to help them to complete this transition as smoothly as possible, without compromising patient care.
Global Warming and HFAs
There is a large and growing need for effective treatment of respiratory disease. On a worldwide basis, the great majority of patients who receive inhalation therapy rely on the MDI (Metered Dose Inhaler) for delivery of their medication. MDIs account for 70 percent of all inhalation therapy in the countries with the largest populations of respiratory disease.
HFA 134a and HFA 227ea are the only known suitable propellants for MDIs. No other compounds are proven to meet the stringent criteria required for a propellant, which is inhaled by a patient on a daily basis.
The quantity of HFAs needed for MDIs is extremely small. Other greenhouse gas emissions vastly overshadow expected emissions from HFA MDIs. It is estimated that the use of HFAs for MDIs in the year 2015 will be no more than 2-3% of the total demand for HFCs on a GWP weighted basis (CO2
equivalents). In addition, the total emissions of HFCs in 2015 are estimated to be about 2% of the total greenhouse gas emissions in 2015. HFAs are not implicated in ozone depletion, and have significantly lower global warming potentials than the CFCs they replaced.
It is important to note that all manufactured devices have some impact on the environment. Medical devices are no exception. However, the environmental effects of medical devices must be viewed in the context of their critical role in patient care. Even so in recent years there has been a trend to reduce the HFA quantity used for each dose, improved designs to ensure maximum use from each MDI, and a trend to recover HFAs from unused batches of MDIs. All these activities have minimised emissions from use of MDIs.
In May 1990, the International Pharmaceutical Aerosol Consortium for Toxicity testing of HFA134a for use in MDI's (IPACT I), came into being. In December of the same year MDI manufacturers formed a second testing consortium, IPACT II, to conduct necessary toxicology tests for pharmaceutical application of HFA 227ea.
IPACT I and IPACT II undertook extensive testing programmes designed to meet the most stringent regulatory requirements. HFA 134a and HFA 227ea were found to be essentially biologically inert, with mild clinical effects only at extremely high dose levels. By the end of 1995, the Committee for Proprietary Medicinal Products (CPMP)
of the European Union had issued assessments of HFA 134a and HFA 227ea concluding that each represented a..."suitable alternative to CFCs currently used in the formulation of medicinal products, including metered dose inhalers for treatment of asthma."
The two compounds have been evaluated and are shown to be safe for use in MDIs. As of 2010, HFA MDIs have been approved for use in the vast majority of countries around the world.
For information on regulatory status click here